2-Deoxy nucleosides, synthesis

A reaction which is analogous to the orthoester synthesis but which utilises glycosyl oxazolines affords means of synthesising, 2-trans-2 amino-2-deoxy-glycoside derivatives. Treatment of the gluco compomd (17) with phenol in the presence of toluene- -sulphonic acid thus gave the glycoside (18), and it was also utilised in a nucleoside synthesis 48). 

Xylopyranoside, methyl 3-amino-3-deoxy-a-D-, deamination of, in nucleoside synthesis, 70... 

As a Chiral Starting Material in L Amino Sugar and l-Nucleoside Synthesis. The recent improved synthetic access to the (45)-aldehyde has facilitated non-natural sugar and nucleoside synthesis. Asymmetric synthesis of several L-amino sugars has been reported. Julia olefination of the (45)-aldehyde with the sulfone afforded the key olefin intermediate as a 4 1E/Z mixture, which was elaborated via Sharpless asymmetric dihydroxylation (SAD) and protecting group interchange to afford the protected 2-deoxy-2-amino-L-mannopyranose (eq 4). ... 

Brothwick, A. D., Evans, D. N., Kirk, B. E., et al. (1990) Fluoro carbocyclic nucleosides synthesis and antiviral activity of 2 -and 6 -(luoro carbocyclic pyrimidine nucleosides including carbocyclic l-(2-deoxy-2-fluoro-P-d-arabinofuranosyl)-5-methyluracil and carbocyclic l-(2 -deoxy-2-fluoro-P-d-arabinofuranosyl)5-iodouracil. J. Med. Chem., 33, 179-186. 

A novel solid phase method for the synthesis of 2 -amino-2 -deoxynucleoside 5 -triphosphates has been developed in which the 3 -azidonucleoside precursors are first linked to support-bound triphenylphosphine as their phosphinimines 116. Following conversion into the triphosphate, the desired 2 -amino-2 -deoxy-nucleoside 5 -triphosphates are released from the support by treatment with ammonia in the Staudinger reaction. ... 

An illustration of the potential value of 2,3-unsaturated furanoid compounds, particularly in nucleoside synthesis, is the preparation, by way of an epoxy intermediate, of a crystalline compound claimed to be ethyl 3-amino-3-deoxy-DL-arabinofuranoside from racemic 2-eth-oxy-2,5-dihydro-5-(tetrahydropyranyloxymethyl)furan (41, R = OEt,... 

In summary, the nucleoside phosphorylases provide a regio- and stereo-specific route for nucleoside synthesis which is applicable to nucleoside analogs which are modified in either the base or the sugar moiety. These processes provide good yields of products in most cases without the extensive protection and deprotection steps involved in traditional chemical synthesis of nucleosides. Application of this strategy to the synthesis of 2 -deoxy- and 2, 3 -dideoxynucleosides was reported with the use of N-deoxyribosyl transferase from Lactobacillus species1301, 312). 

S-ethyl-3-thio-D-xt/Zo isomer, and Raney nickel desulfurization of 6-amino-9- (2-first synthesis of a naturally occurring purine 2-deoxy-nucleoside to be reported. A number of nucleoside analogs were prepared by modification of the purine moiety before desulfurization. ... 

Also lying in the spongonucleoside field was Dr. Baker s novel synthesis of the yS-D-arabinofuranosylpyrimidines utilizing 2-0-acetyl-5-0-methoxycarbonyl-3-O-p-tolylsulfonyl-D-xylofuranosyl chloride, the halide that had been used in the synthesis of 2 -deoxyadenosine. When this halide was condensed with mercury derivatives of thymine and 5-fluoro-uracil and the products deacylated with base, l-yS-n-arabinofuranosyl-thymine and -5-fluorouracil were obtained directly, in reactions that proceeded by way of the 2,3-anhydro-n-ribofuranosides and the 2,2 -anhydronucleosides. These studies were later expanded by others, in synthetic work that has provided alternative paths to purine deoxy-nucleosides and /2-D-arabinosyIpurines, and they anticipated many of the syntheses of arabinosylcytosine (an important antitumor agent) that proceed by way of 2,2 -anhydronucleosides. 

Osmylation of the chirally masked 2-alkoxypent-3-enal 1 and subsequent functional group manipulations furnished enantiopure 5-deoxy-L-lyxose and -xylose derivatives. A new preparation of 5-deoxyribonolactone derivative 2 from ribonolactone by tributyltin hydride reduction of a 5-chloro-5-deoxy intermediate has been published. Conversion of compound 2 to a 5 -deoxy-nucleoside analogue is covered in Chapter 20. A multistep synthesis of methyl 5-0-benzoyl-2,3-dideoxy-P-D-g/ycero-pentofuranose (4) from D-xylose involving Raney nickel desulfurization of compound 3 (see Chapter 11) has been described. Several deoxy-ketoses have been prepared by Raney nickel desulfurization of 1-thio-ketose derivatives obtained by enzyme-catalysed aldol condensations (see Vol. 29, Chapter 2, Scheme 1). An example is given in Scheme 1. ... 

This reaction has found widespread application in organic synthesis, especially in the preparation of deoxy carbohydrates, deoxy nucleosides, and nucleotides. In addition, this reaction can also be applied for converting aldehydes/ketones to alkanes after the reduction of the carbonyl groups. Unfortunately, this reaction has failed in a few... 

Other references to nucleoside antibiotics, including microbial synthesis of 2 -amino-2 -deoxy-nucleosides and Ara-A, the synthesis of oc-2 -deoxynucleosides, and the synthesis of radio-labelled... 

Hfebabecky H, Beranek J (1978) 5 -halogeno-2, 3 -cyclic sulphite isomers in the preparation of 5 -halogeno nucleosides. Synthesis of 5 -deoxyuridine and 5 -deoxy-5-fluorouridine. Nucleic Acids Res 5 1029-1040... 

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